The term microelectromechanical system (MEMS) is often used to refer to small integrated devices or systems that combine electrical and mechanical components. Microphones may be implemented as MEMS, e.g., small microphones comprising mechanical components such as membranes and electrical components for measuring sound pressure levels.
A MEMS microphone includes a pressure-sensitive membrane or diaphragm disposed in a silicon chip. The MEMS microphone (also referred to as MEMS sensor) may be packaged together with an amplifier. The MEMS microphone and the amplifier may be located on different chips or on the same chip. The MEMS microphone may also include an analog-to-digital converter (ADC) circuit making it a digital MEMS microphone, also referred to as a digital silicon microphone (SiMIC). Digital silicon microphones are widely used in various systems and applications such as mobile phones, laptops and other digital mobile devices.
Sensitivity requirements for digital SiMICs may vary drastically depending on the applications. High signal-to-noise ratios are expected of modern digital SiMICs. In addition to supporting audio band signal transmission, digital SiMICs may support other frequency band of operation, e.g., ultra-sound band. There is a need for high-performance digital SiMICs that can support different performance requirements and/or different frequency bands of operation.